Part # Technical Article Set-Top Box LNBTVSx-22xx Tvs Clamping Diodes TA0321 datasheet

Part Manufacturer: ST Microelectronics

ST Microelectronics

Part Description: Lightning protection or LNB supply and control voltage regulator


Part Details:

TA0321 TECHNICAL ARTICLE Lightning protection for LNB supply and control voltage regulator Introduction Communication satellites operate within two frequency bands for TV/Broadband service broadcast signals, C Band and Ku Band. The C Band overall frequency spectrum is 4.0 - 8.0 GHz, while the Ku Band overall frequency spectrum is 10.7 - 18.4 GHz. Within these bands each satellite has a specific uplink and downlink frequency allocation. For example: Ku Band downlink frequency is 10.7 - 12.75 GHz and uplink frequency is 17.3 - 17.8 GHz. C Band downlink frequency is 3.7 - 4.2 GHz and uplink frequency is 5.925 - 6.425 GHz To use the frequencies that are available for satellite broadcast as efficiently as possible, and to accommodate an additional number of channels within a given frequency band, the transmission signal can be formatted to be either vertical and horizontal, or circular right-hand and circular left-hand simultaneously per frequency. UPLINK DOWNLINK September 2006 Rev 2 1/12 www.st.com What is a Low Noise Block (LNB)? TA0321 1 What is a Low Noise Block (LNB)? An LNB is a low noise block module, placed on the focus of the satellite dish antenna (parabola) that provides the following functions: Down conversion of the incoming signal from GHz range to the 910 - 2150 MHz (for Europe) range called "first conversion signal". This conversion allows the signal to be carried by an inexpensive coaxial cable towards the receiver. Signal amplification with good noise figure. The LNB improves the first conversion signal level through the use of a built-in low noise amplifier. Selection of Vertical or Horizontal polarization. Selects operating band by switching its internal oscillator from Low band to High band when the LNB "receives" a 22 kHz tone. Specifically, the local oscillator (LO) frequency changes from 9.75 to 10.6 GHz. ­ C Band - LO frequency 9.75 GHz ­ Ku Band - LO frequency 10.6 GHz Miscellaneous functions based on 22kHz tone PPM encoding, as discussed later in this paper. Figure 1. OMNI-LNB architecture RF Input Antenna Power supply feed and system control H X Waveguide LNA and RHCP transition Polarization LNB Polaraization


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Technical Article Set-Top Box LNBTVSx-22xx Tvs Clamping Diodes TA0321.pdf Datasheet